The invention generally relates to a manifold system for a fuel cell stack.
A fuel cell is an electrochemical device that converts chemical energy produced by a reaction directly into electrical energy. For example, one type of fuel cell includes a proton exchange membrane (PEM), often called a polymer electrolyte membrane, that permits only protons to pass between an anode and a cathode of the fuel cell. At the anode, diatomic hydrogen (a fuel) is reacted to produce hydrogen protons that pass through the PEM. The electrons produced by this reaction travel through circuitry that is external to the fuel cell to form an electrical current. At the cathode, oxygen is reduced and reacts with the hydrogen protons to form water. The anodic and cathodic reactions are described by the following equations:
H2xe2x86x922H++2exe2x88x92at the anode of the cell, and
O2+4H++4exe2x88x92xe2x86x922H2O at the cathode of the cell.
Because a single fuel cell typically produces a relatively small voltage (around 1 volt, for example), several fuel cells may be formed out of an arrangement called a fuel cell stack to produce a higher voltage. The fuel cell stack may include plates (graphite composite or metal plates, as examples) that are stacked one on top of the other, and each plate may be associated with more than one fuel cell of the stack. The plates may include various channels and orifices to, as examples, route the reactants and products through the fuel cell stack. Several PEMs (each one being associated with a particular fuel cell) may be dispersed throughout the stack between the anodes and cathodes of the different fuel cells.
Certain openings of the plates of the stack typically are aligned for purposes of forming passageways for communicating reactants and coolant throughout the stack. Connections must be made between these passageways of the stack and various conduits of the system. For example, the passageway of the stack that is associated with the fuel that is supplied to the stack needs to be connected to a fuel input line that communicates fuel from a fuel processor. These connections between the stack passageways and the conduits of the fuel cell system may consume a significant part of the time needed to assemble the fuel cell system, and this assembly time may directly affect the overall cost of the fuel cell system.
Thus, there is a continuing need for an arrangement that addresses one or more of the problems that are stated above.
In an embodiment of the invention, a fuel cell system includes a fuel cell stack, a manifold and a hinge. The manifold forms a sealed interface to communicate reactants with the stack, and the hinge forms a pivotable connection between the stack and the manifold.
In another embodiments of the invention, a fuel cell system includes a fuel cell stack, a manifold and a separator (a gas/water separator, for example). The manifold communicates flows with the stack, and the separator is disposed in the manifold to collect water from one of the flows.
Advantages and other features of the invention will become apparent from the following description, from the drawing and from the claims.